Which of the following compounds gives a ketone with a Grignard reagent?

Give names of the reagents to bring about the following transformations:
$(i)$ $\text{Hexan-}1\text{-ol}$ to $\text{hexanal}$
$(ii)$ $\text{Cyclohexanol}$ to $\text{cyclohexanone}$
$(iii)$ $p\text{-Fluorotoluene}$ to $p\text{-fluorobenzaldehyde}$
$(iv)$ $\text{Ethanenitrile}$ to $\text{ethanal}$
$(v)$ $\text{Allyl alcohol}$ to $\text{propenal}$
$(vi)$ $\text{But-}2\text{-ene}$ to $\text{ethanal}$

Toluene is converted to benzaldehyde by oxidation with.......

Describe the method of preparation of aldehydes from nitrile and ester compounds by reaction with $DIBAL-H$.

Identify the compound $C$ in the following sequence:
$(CH_3)_2CHCH_2C \equiv N$ $\xrightarrow{HCl, H_2O} \text{compound } A$ $\xrightarrow[2. H_2O]{1. LiAlH_4} \text{compound } B$ $\xrightarrow{PCC, CH_2Cl_2} \text{compound } C$

Consider the following reactions:
$C_2H_2 + H_2O \xrightarrow[333 \ K]{Hg^{2+} / H^{+}} [X] \stackrel{\text{Isomerisation}}{\rightleftharpoons} Y$
$Y$ cannot be obtained from which of the following reactions?